Nullable Types in c# 2.0

Nullable types are instances of the System.Nullable struct, which helps value type (int , float etc..) to hold null value. This scenario comes when you are dealing with database and database software support null under value type but not front end language(c#, vb.net). c# 2.0 introduce nullable types to enable value types to hold null value;

Syntax:

            int num1 = null;  // Invalid

             int? num1 = null;  // Valid

Paging, searching sorting using asp.net gridview

  UI Design:-

  Add ajax control toolkit at the top of page
<%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="asp" %>

  <form id="form1" runat="server">
     <asp:ToolkitScriptManager ID="toolManager" runat="server" />
    
    <div>
    <asp:UpdatePanel ID="updMain" runat="server"><ContentTemplate>
        <center>
                <div class="Subdiv" style="background-color: #DFDFDF;">
             <center>
            <asp:Table ID="Table1" runat="server"><asp:TableRow><asp:TableCell><asp:DropDownList ID="drplSearchType" Width="100" runat="server" /></asp:TableCell><asp:TableCell><asp:TextBox ID="txtTextSearch" AutoPostBack="true" runat="server" OnTextChanged="SearchTextChanged"/><asp:TextBoxWatermarkExtender
                    ID="TextBoxWatermarkExtender1" runat="server" WatermarkText="Search" TargetControlID="txtTextSearch" Enabled="true">
                </asp:TextBoxWatermarkExtender>
            </asp:TableCell><asp:TableCell><asp:ImageButton Width="20" Height="23" runat="server" ImageUrl="~/Images/search_button.png" BackColor="White" ID="imgbtnSearch" OnClick="imgbtnSearch_Click" /></asp:TableCell><asp:TableCell>&nbsp&nbsp&nbsp&nbsp&nbsp<asp:Label ID="lblPageNo" runat="server" Text="Page No." /><asp:DropDownList ID="drplPageNo" runat="server" Width="100" AutoPostBack="true" OnSelectedIndexChanged="drplPageNo_SelectedIndexChanged" /></asp:TableCell></asp:TableRow></asp:Table>
           
             </center>
            </div>
        </center>
        <center>
        <asp:UpdatePanel ID="UpdateGridview" runat="server">
         <ContentTemplate>
            <asp:GridView runat="server" ID="grdInventory" DataKeyNames="pkint_InventoryId" AutoGenerateColumns="False"
                      onsorting="grdInventory_Sorting1" width="890" AllowSorting="true"
                                    onrowcommand="grdInventory_RowCommand"><RowStyle BackColor="#EFF3FB" />
                    <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                    <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                    <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                    <AlternatingRowStyle BackColor="White" />
                    <Columns>
                  
                     <asp:TemplateField SortExpression="pkint_InventoryId" HeaderText="InventoryId"
                            ItemStyle-HorizontalAlign="Center" ControlStyle-Width="100">
                            <HeaderStyle ForeColor="#E1E1FF" />
                            <ItemTemplate>
                                <asp:Label ID="lblInventoryId" Text='<%# Eval("EmpId") %>' Width="100" runat="server" /></ItemTemplate>
                            <ItemStyle HorizontalAlign="Center" />
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Sub SectionId" SortExpression="fkint_SubSectionNo"
                             ControlStyle-Width="50" ItemStyle-HorizontalAlign="Center">
                             <HeaderStyle ForeColor="#E1E1FF" />
                            <ItemTemplate>
                                <asp:Label ID="lblSubSectionNo" Text='<%# Eval("EmpName") %>' Width="50" runat="server" /></ItemTemplate>
                            <ItemStyle HorizontalAlign="Center" />
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="LocationId" ControlStyle-Width="100" SortExpression="fkint_LocationId"
                            ItemStyle-HorizontalAlign="Center">
                            <HeaderStyle ForeColor="#E1E1FF" />
                            <ItemTemplate>
                                <asp:Label ID="lblLocationId" Text='<%# Eval("EmpAddress") %>' Width="100" runat="server" /></ItemTemplate>
                            <ItemStyle HorizontalAlign="Center" />
                        </asp:TemplateField>
                      

                     <asp:TemplateField HeaderText="Edit" ControlStyle-Width="25">
                    <ItemTemplate>
                    <asp:ImageButton ID="imgbtn" ImageUrl="~/Images/Edit.jpg" runat="server" OnClick="imgbtn_Click"  ToolTip="Edit" Width="25" Height="25" />
                    </ItemTemplate>
                    </asp:TemplateField>

                     <asp:TemplateField HeaderText="Delete" ControlStyle-Width="25">
                    <ItemTemplate>
                    <asp:ImageButton ID="imgDelete" ImageUrl="~/Images/imagesCA03VBLD.jpg"  ToolTip="Delete" runat="server" OnClick="imgDelete_Click" Width="25" Height="25"  />
                    </ItemTemplate>
                    </asp:TemplateField>

               </Columns>
</asp:GridView>

    <div style="width:893px; background-color: #D3E6EB;height:36px;">
    <asp:Table ID="Table2" runat="server"><asp:TableRow><asp:TableCell>
            <asp:ImageButton ID="btnSortFirst" Width="30" Height="30" 
                Text="First" Imageurl="~/Images/Button-Rewind-icon.png" Font-Bold="true" runat="server" ToolTip="First Record"
                onclick="btnSortFirst_Click"/>   </asp:TableCell><asp:TableCell><asp:ImageButton Width="30px" Height="30px"
                                        ID="btnSortPrevious" Text="Previous" ToolTip="Previous"
                runat="server" Font-Bold="true" ImageUrl="~/Images/go_previous_blue.png"
                onclick="btnSortPrevious_Click" /></asp:TableCell>
                <asp:TableCell><asp:ImageButton ID="btnSortNext" Font-Bold="true"  ToolTip="Next"  ImageUrl="~/Images/go_next_blue.png" Width="30" Height="30"
                 Text="Next" runat="server" onclick="btnSortNext_Click" /> </asp:TableCell><asp:TableCell>
            <asp:ImageButton Width="30px" Height="30px"  ToolTip="Last Record"
                              ID="btnSortLast" Text="Last" Font-Bold="true"
                 runat="server" onclick="btnSortLast_Click" ImageUrl="~/Images/Button-Fast-Forward-icon.png"/></asp:TableCell>
                               <asp:TableCell><asp:Label ID="lblCount" runat="server"/></asp:TableCell><asp:TableCell><asp:Label ID="lblSetIndex" CssClass="FooterText" Height="20" Text="Page Size" runat="server"/></asp:TableCell><asp:TableCell><asp:TextBox ID="txtPageSize" CssClass="footerDropList" runat="server" AutoPostBack="True"/></asp:TableCell><asp:TableCell><asp:ImageButton ID="imgbtnPageSize" runat="server" Width="30" Height="30" ImageUrl="~/Images/874420,1327419752,2.jpg" onclick="imgbtnPageSize_Click" ToolTip="Change Page Size"/>&nbsp&nbsp <asp:ImageButton ID="btnAdd" runat="server" Height="20" Width="20" ImageUrl="~/Images/Add-icon.png" ToolTip="Add New Record" CssClass="footerDropList" onclick="btnAdd_Click" /></asp:TableCell></asp:TableRow></asp:Table>
                          <br /><br />
           <asp:Label ID="lblErro" runat="server" Text="No more records available" Visible="false"  ForeColor="Red"/>
        </div>
        </ContentTemplate>
        </asp:UpdatePanel>
        </center>
        </ContentTemplate></asp:UpdatePanel>
       
        <center>
        <div>
            <asp:Button ID="btnShowPopup" runat="server" Style="display: none" />
            <asp:Button ID="btnShowAddpopup" runat="server" Style="display: none" />
            <asp:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="btnShowPopup"
                PopupControlID="pnlpopup" CancelControlID="btnCancel" BackgroundCssClass="modalBackground">
            </asp:ModalPopupExtender><asp:Panel ID="pnlpopup" runat="server" BackColor="White" Width="400px" Style="display: none">
                <asp:UpdatePanel ID="UpdateModal" runat="server">
                    <ContentTemplate>
                       <table width="100%" style="width: 100%; height: 100%" cellpadding="0" cellspacing="0">
                            <tr style="background-color: #3568FF;">
                                <td colspan="2" style="height: 10%; color: White; font-weight: bold; font-size: larger"
                                    align="center">
                                    Emp Details </td></tr><tr>
                                <td align="right" style="width: 45%">
                                    <asp:Label ID="lblInventoryId" runat="server" Text="Inventory Id" />
                                </td>
                                <td>
                                    <asp:Label ID="lblInventoryIdval" runat="server"></asp:Label></td></tr><tr>
                                <td align="right">
                                    EmpId: </td><td>
                                    <asp:TextBox ID="EmpId" runat="server"></asp:TextBox></td></tr><tr>
                                <td align="right">
                                    EmpName: </td><td>
                                    <asp:TextBox ID="EmpName" runat="server" />
                                </td>
                            </tr>
                            <tr>
                                <td align="right">
                                   EmpAdd: </td><td>
                                    <asp:TextBox ID="EmpAdd" runat="server" />
                                </td>
                            </tr>
                        </table>
                    </ContentTemplate>
                </asp:UpdatePanel>
                <table>
                    <tr>
                        <td>
                        </td>
                        <td>
                            <asp:Button ID="btnUpdate" CommandName="Update" runat="server" Text="Edit" OnClick="btnUpdate_Click" />
                            <asp:Button ID="btnCancel" runat="server" Text="Cancel" />
                        </td>
                    </tr>
                </table>
            </asp:Panel>
            <asp:ModalPopupExtender ID="AddPopup" runat="server" TargetControlID="btnShowAddpopup"
                PopupControlID="AddPanel" CancelControlID="btnCancel" BackgroundCssClass="modalBackground">
            </asp:ModalPopupExtender><asp:Panel ID="AddPanel" runat="server" BackColor="White" Width="400px" Style="display: none">
                <asp:UpdatePanel ID="UpdateAddpopup" runat="server">
                    <ContentTemplate>
                        <table width="100%" style="width: 100%; height: 100%" cellpadding="0" cellspacing="0">
                            <tr style="background-color: #3568FF">
                                <td colspan="2" style="height: 10%; color: White; font-weight: bold; font-size: larger"
                                    align="center">
                                    Inventory Details </td></tr><tr>
                                <td align="right">
                                    SubSectionId: </td><td>
                                    <asp:TextBox ID="txtaSubsectionId" runat="server"></asp:TextBox></td></tr><tr class="RowMargin">
                                <td align="right">
                                    Location Id: </td><td>
                                    <asp:TextBox ID="txtaLocationId" runat="server" />
                                </td>
                            </tr>
                            <tr class="RowMargin">
                                <td align="right">
                                    Region Id: </td><td>
                                    <asp:TextBox ID="txtaRegionId" runat="server" />
                                </td>
                            </tr>
                            <tr class="RowMargin">
                                <td align="right">
                                    Inventory Name: </td><td>
                                    <asp:TextBox ID="txtaInventoryName" runat="server" />
                                </td>
                            </tr>
                            <tr class="RowMargin">
                                <td align="right">
                                    Asset Type: </td><td>
                                    <asp:TextBox ID="txtaAssetType" runat="server" />
                                </td>
                            </tr>
                        </table>
                    </ContentTemplate>
                </asp:UpdatePanel>
                <table>
                    <tr>
                        <td>
                        </td>
                        <td>
                            <asp:Button ID="btnAddPopup" CommandName="Add" runat="server" Text="ADD" OnClick="btnAddPopup_Click" />
                            <asp:Button ID="btnAddPopupCancel" runat="server" Text="Cancel" />
                        </td>
                    </tr>
                </table>
            </asp:Panel>
            </div>
        </center>
        </div>
        <asp:Label ID="lblIndex" runat="server" />
        <asp:Label ID="lblLastCount" runat="server" />
    </form>



Style sheet:-
 <style type="text/css">
        .GridTitle
        {
            background: #3568FF;
            color: White;
            width: 890px;
            font-size: larger;
            font-weight: bold;
            height:25px;
        }
        .GridHeader
        {
            background:#45697C;
            height:30px;
        }
         .Subdiv
        {
            width:893px;
            height:30px;
        }
        .modalBackground
        {
            background-color: Gray;
            filter: alpha(opacity=60);
            opacity: 0.6;
            z-index: 10000;
        }
        .buttonOpacity
        {
            filter: alpha(opacity=60);
            opacity: 0.6;
        }
    </style>

Script:-

  <script type="text/javascript">
        function RefreshUpdatePanel() { __doPostBack('<%= txtTextSearch.ClientID %>', ''); };
    </script>




Code Behind :-
 public partial class test : System.Web.UI.Page
    {
 int Count;
        int PageNo;
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                lblIndex.Text = "1";
                Session["PageStart"] = "1";
                Session["PageSize"] = "10";
                Session["SortExpression"] = "EmpId";
                Session["SortDirection"] = "ASC";


                drplSearchType.Items.Add("Search type");
                drplSearchType.Items.Add("All");
                drplSearchType.Items.Add("Emp Id");
                drplSearchType.Items.Add("EmpName");
                drplSearchType.Items.Add("EmpAddress");
                drplSearchType.SelectedIndex = 0;
                btnSortFirst.Enabled = false;
                btnSortPrevious.Enabled = false;
                objBL_Ienumerable = new BL_Ienumerable();
                grdInventory.DataSource = objBL_Ienumerable.Get_SPData(0, 10, Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, "", "", out Count, out PageNo);
                grdInventory.DataBind();
                Session["LastIndex"] = PageNo.ToString();
                Session["PageNo"] = PageNo.ToString();
                lblCount.Text = "0 to 10 of " + Count;
                txtPageSize.Text = "10";
                BindPageDropDownList(PageNo);
            }
        }

 private void BindPageDropDownList(int PageNo)
        {

            for (int i = 1; i <= PageNo; i++)
            {
                drplPageNo.Items.Add(i.ToString());
            }
        }
    private void BindGridview(int PageIndex, int PageSize, string SortExpression, string SortDirection, int NewPageIndex, string SearchText, string SearchType, out int Count, out int PageNo)
        {

            int IndexStart;
            int IndexEnd;
            objBL_Ienumerable = new BL_Ienumerable();
            grdInventory.DataSource = objBL_Ienumerable.Get_SPData(PageIndex, PageSize, SortExpression, SortDirection, NewPageIndex, SearchText, SearchType, out Count, out PageNo);
            grdInventory.DataBind();
            IndexStart = ((PageIndex * PageSize) - PageSize);
            IndexEnd = (PageIndex * PageSize);
            txtPageSize.ReadOnly = false;

            if (Count < PageSize && txtTextSearch.Text != "")
            {
                DisableNextButton(); DisablePreviousButton(); txtPageSize.ReadOnly = true;
                lblCount.Text = IndexStart + " to " + Count + " of " + Count;
                imgbtnPageSize.Enabled = false;
            }
            else if ((IndexStart + PageSize) >= Count)
            {
                lblCount.Text = (IndexStart + 1) + " to " + Count + " of " + Count;
                DisableNextButton();
                EnablePreviousButton();
                txtPageSize.ReadOnly = true;
                imgbtnPageSize.Enabled = false;
            }

            else if (PageIndex == 1)
            {
                lblCount.Text = (IndexStart + 1) + " to " + IndexEnd + " of " + Count;
                DisablePreviousButton();
                EnableNextButton();
                imgbtnPageSize.Enabled = true;
            }
            else
            {
                lblCount.Text = (IndexStart + 1) + " to " + IndexEnd + " of " + Count;
                EnableNextButton();
                EnablePreviousButton();
                imgbtnPageSize.Enabled = true;
            }
            lblIndex.Text = PageIndex.ToString();
            Session["sLast"] = PageNo.ToString();
            drplPageNo.Items.Clear();
            BindPageDropDownList(PageNo);
            if (PageNo > 0)
                drplPageNo.SelectedIndex = PageIndex - 1;
            //if(Convert.ToInt32(Session["PageStart"])!= 0)
            //    lblCount.Text = Convert.ToInt32(Session["PageStart"]) + " to " + (Convert.ToInt32(Session["PageStart"]) + Convert.ToInt32(txtPageSize.Text) -1) + " of " + Count;
            //else
            //    lblCount.Text = Convert.ToInt32(Session["PageStart"]) + " to " + (Convert.ToInt32(Session["PageStart"]) + Convert.ToInt32(txtPageSize.Text)) + " of " + Count;
        }


 #region Sorting Grdiview Column
        private string SortDirection
        {
            get
            {
                if (ViewState["SortDirection"] != null)
                    return (String)ViewState["SortDirection"];
                else return "ASC";
            }
            set
            {
                ViewState["SortDirection"] = value;
            }
        }
        private string SortExpression
        {
            get
            {
                if (ViewState["SortExpression"] != null)
                    return ViewState["SortExpression"].ToString();
                else return null;
            }
            set
            {
                ViewState["SortExpression"] = value;
            }
        }
        protected void grdInventory_Sorting1(object sender, GridViewSortEventArgs e)
        {
            Session["SortDirection"] = "DESC";
            Session["Index"] = "0";
            if (SortExpression != null)
            {
                if (SortExpression == e.SortExpression && SortDirection == "ASC")
                {
                    SortDirection = "DESC";
                    Session["SortDirection"] = "DESC";
                    DisablePreviousButton();
                }
                else
                {
                    SortDirection = "ASC";
                    Session["SortDirection"] = "ASC";
                }
            }
            SortExpression = e.SortExpression;
            Session["SortExpression"] = SortExpression.ToString();
            BindGridview(1, Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, "search", "col", out Count, out PageNo);

            EnableNextButton();
            DisablePreviousButton();
        }
        #endregion


#region Paging Buttons

        protected void btnSortFirst_Click(object sender, ImageClickEventArgs e)
        {
            lblIndex.Text = "1";
            BindGridview(Convert.ToInt32(lblIndex.Text), Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.Text, out Count, out PageNo);
            DisablePreviousButton(); EnableNextButton();
            //Session["PageStart"] = "1";
            lblErro.Visible = true;
            lblErro.Text = "No more records available, We are on First page";
        }

        protected void btnSortPrevious_Click(object sender, ImageClickEventArgs e)
        {
            int Index = Convert.ToInt32(lblIndex.Text);
            if (Index > 1)
            {
                Index = Convert.ToInt32(lblIndex.Text) - 1;
                BindGridview(Index, Convert.ToInt32(txtPageSize.Text), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.Text, out Count, out PageNo);
                EnableNextButton();
                //Session["PageStart"] = (Convert.ToInt32(Session["PageStart"]) - Convert.ToInt32(txtPageSize.Text)).ToString();
                //int PageStart = Convert.ToInt32(Session["PageStart"]);
                //lblCount.Text = PageStart + " to " + (PageStart + Convert.ToInt32(txtPageSize.Text) - 1) + " of " + Count;
            }
            lblErro.Visible = false;
            if (Index == 1)
            {
                DisablePreviousButton();
                lblErro.Visible = true;
                lblErro.Text = "No more records available, We are on First page";
            }
            lblIndex.Text = Index.ToString();

        }

        protected void btnSortNext_Click(object sender, ImageClickEventArgs e)
        {
            int Index = Convert.ToInt32(lblIndex.Text);
            int Last = Convert.ToInt32(Session["LastIndex"]);

            //Session["PageStart"] = (Convert.ToInt32(Session["PageStart"]) + Convert.ToInt32(Session["PageSize2"]));
            Session["PageSize2"] = txtPageSize.Text;
            //Session["PageSize"] = (Convert.ToInt32(Session["PageSize"]) + Convert.ToInt32(txtPageSize.Text));
            if (Index < Last)
            {
                Index = Convert.ToInt32(lblIndex.Text) + 1;
                BindGridview(Index, Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.Text, out Count, out PageNo);
                EnablePreviousButton();
                //Session["PageStart"] = (Convert.ToInt32(Session["PageStart"]) + Convert.ToInt32(txtPageSize.Text)).ToString();
                //int PageStart = Convert.ToInt32(Session["PageStart"]);
                //lblCount.Text = PageStart + " to " + (PageStart + Convert.ToInt32(txtPageSize.Text) - 1) + " of " + Count;
            }
            lblErro.Visible = false;
            if (Index == Last)
            {
                DisableNextButton();
                txtPageSize.ReadOnly = true;
                lblErro.Text = "No more records available, We are on last page";
                lblErro.Visible = true;
            }
            lblIndex.Text = Index.ToString();

        }

        protected void btnSortLast_Click(object sender, ImageClickEventArgs e)
        {
            lblIndex.Text = Session["LastIndex"].ToString();
            BindGridview(Convert.ToInt32(lblIndex.Text), Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.Text, out Count, out PageNo);
            EnablePreviousButton(); DisableNextButton();
            //Session["PageStart"] = (Count - grdInventory.Rows.Count + 1).ToString();
            //int PageStart = Convert.ToInt32(Session["PageStart"]);
            txtPageSize.ReadOnly = true;
            lblErro.Visible = true;
            lblErro.Text = "No more records available, We are on last page";
        }
        #endregion

   #region Add New Record
        protected void btnAdd_Click(object sender, ImageClickEventArgs e)
        {
            this.AddPopup.Show();
            EmpName.Text = "";
            EmpAdd.Text = "";
        }
        #endregion


        protected void drplSetIndex_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

  #region Page size Button
        protected void imgbtnPageSize_Click(object sender, ImageClickEventArgs e)
        {
          
            lblIndex.Text = "1";//((PageSize * Index) / tbxPageSize).ToString();
            if (Convert.ToInt32(lblIndex.Text) == 0)
                lblIndex.Text = "1";
         
            Session["PageSize"] = Convert.ToInt32(txtPageSize.Text);
            Session["PageNo"] = PageNo.ToString();
            BindGridview(Convert.ToInt32(lblIndex.Text), Convert.ToInt32(txtPageSize.Text), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, "search", drplSearchType.SelectedItem.Text, out Count, out PageNo);
            drplPageNo.Items.Clear();
            BindPageDropDownList(PageNo);
            Session["LastIndex"] = PageNo.ToString();
        }
        #endregion

        #region Button Enable and Disable Code
        public void DisableNextButton()
        {
            btnSortLast.Enabled = false;
            btnSortNext.Enabled = false;
        }
        public void EnableNextButton()
        {
            btnSortLast.Enabled = true;
            btnSortNext.Enabled = true;
        }
        public void DisablePreviousButton()
        {
            btnSortFirst.Enabled = false;
            btnSortPrevious.Enabled = false;
        }
        public void EnablePreviousButton()
        {
            btnSortFirst.Enabled = true;
            btnSortPrevious.Enabled = true;
        }
        #endregion


  #region Search TextBox

        protected void imgbtnSearch_Click(object sender, ImageClickEventArgs e)
        {
            lblIndex.Text = "1";
            Session["PageSize"] = txtPageSize.Text;
            if (txtTextSearch.Text != "")
            {
                BindGridview(Convert.ToInt32(lblIndex.Text), Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.SelectedItem.Text, out Count, out PageNo);
                drplPageNo.Items.Clear();
                BindPageDropDownList(PageNo);
                lblErro.Text = Count + " records search for given string";
                lblErro.Visible = true;
            }
            else
            {
                BindGridview(Convert.ToInt32(lblIndex.Text), Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.SelectedItem.Text, out Count, out PageNo);
                drplPageNo.Items.Clear();
                BindPageDropDownList(PageNo);
                lblErro.Visible = false;
            }
            Session["LastIndex"] = PageNo.ToString();
        }
        protected void SearchTextChanged(object sender, EventArgs e)
        {

        }
        #endregion


   protected void drplPageNo_SelectedIndexChanged(object sender, EventArgs e)
        {
            lblIndex.Text = drplPageNo.SelectedItem.Text;
            BindGridview(Convert.ToInt32(lblIndex.Text), Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.SelectedItem.Text, out Count, out PageNo);
            int PageSize = PageNo;//((Convert.ToInt32(drplPageNo.SelectedItem.Text) * Convert.ToInt32(txtPageSize.Text)) - Convert.ToInt32(txtPageSize.Text) +1);
            Session["PageStart"] = PageSize.ToString();
            if ((Convert.ToInt32(lblIndex.Text) * Convert.ToInt32(txtPageSize.Text) >= Count))
            {
                lblErro.Text = lblErro.Text = "No more records available, We are on last page";
                lblErro.Visible = true;
            }
            else if ((Convert.ToInt32(lblIndex.Text) == 1))
            {
                lblErro.Text = lblErro.Text = "No more records available, We are on First page";
                lblErro.Visible = true;
            }
            else
                lblErro.Visible = false;
        }
   protected void imgbtn_Click(object sender, ImageClickEventArgs e)
        {
            btnUpdate.Text = "Edit";
            dtGetById = new DataTable();
            ImageButton btndetails = sender as ImageButton;
            lblInventoryIdval.Text = grdInventory.DataKeys[((GridViewRow)((Control)btndetails.NamingContainer)).RowIndex].Value.ToString();
            dtGetById = DL.GetById(lblInventoryIdval.Text);
            for (int i = 0; i < dtGetById.Rows.Count; i++)
            {
                lblInventoryIdval.Text = dtGetById.Rows[i][0].ToString();
                EmpName.Text = dtGetById.Rows[i][1].ToString();
                EmpAddredd.Text = dtGetById.Rows[i][2].ToString();
            }

            this.ModalPopupExtender1.Show();
        }


        protected void imgDelete_Click(object sender, ImageClickEventArgs e)
        {
            ImageButton btndetails = sender as ImageButton;
            objDL = new DL();
            objDL.DeleteRecords(grdInventory.DataKeys[((GridViewRow)((Control)btndetails.NamingContainer)).RowIndex].Value.ToString());
            BindGridview(Convert.ToInt32(lblIndex.Text), Convert.ToInt32(Session["PageSize"]), Session["SortExpression"].ToString(), Session["SortDirection"].ToString(), 0, txtTextSearch.Text, drplSearchType.SelectedItem.Text, out Count, out PageNo);
        }
        #endregion


       Good Luck.........

jquery Pie Chart in .net using google API

 This sample shows you, how to make pie chart using jquery.  The below jquery library file necessary
 for making chart. Its free to use.

 <script type="text/javascript" src="https://www.google.com/jsapi"></script>


Write code on server side function calling from jquery.The sample is for asp.net using c#.

        [WebMethod]
        [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
        public static List<RetUsers> GetSome()
        {
            // avoid circual reference(parent child)
            List<RetUsers> res = new RetUsers().GetAllUser().Select(c => new RetUsers { User_ID = c.User_ID, User_Name = c.User_Name }).ToList();
          
            return res;
        }

   
    public class RetUsers
    {
        public int User_ID { get; set; }
        public string User_Name { get; set; }


        public List<RetUsers> GetAllUser()
        {
            List<RetUsers> lstFood = new List<RetUsers>();
            for (int i = 0; i < 5; i++)
            {
                RetUsers objFood = new RetUsers();
                objFood.User_ID = i;
                objFood.User_Name = "Food" + i;
                lstFood.Add(objFood);
            }
            return lstFood;
        }
    }


jquery code on aspx page. 

  <script type="text/javascript" src="https://www.google.com/jsapi"></script>
  <script src="http://code.jquery.com/jquery-1.4.2.min.js" type="text/javascript"></script>

  <script type="text/javascript">

        // Load the Visualization API and the piechart package.
        google.load('visualization', '1.0', { 'packages': ['corechart'] });
        // Set a callback to run when the Google Visualization API is loaded.
        google.setOnLoadCallback(drawChart);
        // Callback that creates and populates a data table,
        // instantiates the pie chart, passes in the data and     
        // draws it.

        function drawChart() {
            var pie = [];
         
            var data;
            $.ajax(
            {
                type: "POST",
                async: true,
                url: "CallingServer.aspx/GetSome",
                data: {},
                contentType: "application/json; charset=utf-8",
                dataType: "json",

           
                success: function (msg) {
                    var resultAsJson = msg.d // your return result is JS array
                    // Now you can loop over the array to get each object


                    pie.push([['Mushrooms', 3], ['Onions', 1], ['Olives', 1], ['Zucchini', 1], ['Pepperoni', 2]]);
                    // Create the data table.       
                    data = new google.visualization.DataTable();

                    data.addColumn('string', 'User_Name');
                    data.addColumn('number', 'User_ID');
                    for (var i in resultAsJson)
                     {
                        var user = resultAsJson[i]
                        var user_name = user.User_Name
                        data.addRows([['' + user.User_Name + '', user.User_ID]]);
                        // Here you append that value to your label
                     }
                   
                
                    // Set chart options       
                    var options = { 'title': 'How Much Pizza I Ate Last Night', 'width': 400, 'height': 300 };
                    // Instantiate and draw our chart, passing in some options.       
                    var chart = new google.visualization.PieChart(document.getElementById('chart_div'));
                   chart.draw(data, options);
                }
            }
        );
            }
    </script>

Add div tag in html
 <div id="chart_div"></div>  

Implicit Typed Variables

                   Microsoft introduced new features in C# 3.0  named as implicit typed local variables, it is capable to hold any type like int, float, string, complex type etc. Implicitly typed local variable is a variable that can be declared without specifying the .NET type explicitly. It determines type at compile time.
 
              Implicit typed vlocal variables are introduced to support LINQ that create anonymous types in queries for which you want to assign variables. However, they are not only used with LINQ, you can declare and use them in your different programs.

Syntax:-
                   var  name = "Asif";

                   var    --> Keyword
                   name --> Variable name